The present invention relates to an optical device, which is used in a digital camera or the like, an image pickup device, which uses the optical device, and an image pickup system, which includes the image pickup device and an external device; and more particularly to those having an optical system suitable for an image restoration process, which is performed on a taken image.
Conventionally, various image pickup devices are known that take a picture by projecting an image of an object, which is obtained as the light is concentrated through an optical system, onto an image pickup element such as CCD. In such an image pickup device, on an image obtained by an image pickup process, various kinds of image processing are typically performed to process the image in a filter having a predetermined characteristic.
As such a kind of image pickup device capable of image processing, what is disclosed in JP-A-2008-011492 is an image pickup device that includes an optical system, an image pickup element, a conversion means and a signal processing means and uses a first filter and a second filter. The optical system is so formed that, at a focal position and in distances before and behind the focal position, the amounts of focus blur become substantially constant. The image pickup element takes an object's image, which is formed by the optical system. The conversion means corrects the focus blur in the image obtained from the image pickup element, and generates a restored image. The signal processing means performs predetermined image processing on an image signal. The first filter is used, at the time of still image taking mode, for an image restoration process of the conversion means. The second filter is used, at the time of moving image taking mode or when a through-the-lens image is displayed, for an image restoration process of the conversion means.
According to what is disclosed in JP-A-2008-011492, at the time of moving image taking mode or when a through-the-lens image is displayed, the second filter can be used to carry out a simple image restoration process. As a result, without the need for expensive conversion means, the optical system can be simplified, resulting in lower costs. Moreover, it is possible to provide an image pickup device that prevents a restored image from being degraded.